M1: notes model + migration 0002 + notes API (CRUD, trash/restore)

- Note model (owner_id, title, body, color-key, pinned, archived, deleted_at
  soft-delete, timestamps) + board index; NOTE_COLORS palette keys.
- Migration 0002 (notes table + ix_notes_owner_board).
- /api/notes blueprint (login_required): list (?filter=active|archived|trash,
  pinned-then-updated, read via visible_to_user ACL), create, get, patch
  (title/body/color/pinned/archived), trash, restore, permanent delete
  (trash-only). Mutations owner-scoped; empty note rejected (400).
- DB-free unit tests: is_empty_note, normalize_color, palette, serialize,
  auth-guard on list/create.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FRgehjoz7Yv8LkUfADxACm

src/thoughtsync/app.py

@@ -7,6 +7,7 @@ from quart import Quart, jsonify, send_from_directory
 from . import __version__
 from .auth import bp as auth_bp
 from .config import Config
+from .notes import bp as notes_bp
 
 STATIC_DIR = os.path.join(os.path.dirname(__file__), "static")
 
@@ -19,6 +20,7 @@ def create_app() -> Quart:
     app.config["APP_VERSION"] = os.environ.get("APP_VERSION", __version__)
 
     app.register_blueprint(auth_bp)
+    app.register_blueprint(notes_bp)
 
     @app.get("/api/health")
     async def health():